How does oxytocin control the brain's social reward circuit?

Although several studies have pointed to oxytocin, or the "love hormone," as an important factor in promoting sociability, the mechanisms behind this remain unknown. Researchers from Stanford University have now looked into how oxytocin regulates the social reward mechanism in the brain.

Oxytocin, the "love hormone," is a key factor of our social abilities, but not much is known about the mechanisms in which this hormone is involved.

Oxytocin, which is sometimes referred to as the "love hormone," is a hormone and neuropeptide - or neurotransmitter, carrying information through the central nervous system - involved in sociability and sexual interaction. It also plays a role in facilitating biological processes related to childbirth, and bonding with the newborn baby.

Oxytocin is mainly produced in a brain region called the paraventricular nucleus, which is located in the hypothalamus. The hypothalamus is involved in various metabolic processes, including regulating body temperature, determining states of hunger and thirst, and some social behaviors, such as attachment.

Recently, much has been made of oxytocin's role in promoting social behaviors, especially with a view to harnessing its potential in managing conditions such as autism, which impairs social interaction.

Medical News Today, for instance, have recently covered a study suggesting that the hormone could improve sociability in some children with autism.

Now, a new study conducted by Dr. Robert Malenka and a team of researchers from the Stanford University School of Medicine in California now looks at the mechanism behind the social reward system of the brain, pinpointing oxytocin's role in this process.

"[D]eficits in social behavior [due to brain disorders such as autism] profoundly affect [...] quality of life," Dr. Malenka told MNT, "and thus it is critical to understand the underlying abnormalities in brain function that cause [them]."

He continued, saying, "The findings in this paper suggest that one factor contributing to social behavior deficits may be abnormal modulation of the brain's reward circuitry by oxytocin."

A paper detailing the researchers' findings has been published in the journal Science.

The brain's reward mechanism

In the brain, a region called the ventral tegmental area (VTA) communicates with the nucleus accumbens to regulate the system's reward response, which is a circuit telling us that certain activities - such as eating, drinking, and sex - are pleasurable.

Thus, they "encourage" us to keep performing them. This reward mechanism is, in part, what ensures that we thrive and keep on reproducing.

The nerve cells that make up the VTA secrete dopamine, another neurotransmitter, which regulates the sensation of pleasure. Dopamine released in the brain makes us feel good when we perform activities correlated with survival, but abnormal levels of this neurotransmitter have also been linked to addiction and substance abuse.

Dr. Malenka and team were interested in understanding why dopamine is sometimes released abnormally, causing undesirable effects, and what other factors are implicated in the complex reward response mechanism of the brain.

Oxytocin impacted dopamine neurons

Since the reward circuit of mice is similar to that of humans, the researchers used the rodent model to study the mechanism's intricacies in more detail.

In a previous study on mice conducted by Dr. Malenka and colleagues, it became apparent that oxytocin plays an important role in determining social reward responses alongside dopamine. However, it remained unclear exactly how oxytocin impacted the functioning of this circuit.

Now, the researchers reveal that the paraventricular nucleus releases oxytocin in the VTA, which is crucial for promoting prosocial behaviors. Conversely, when the release of oxytocin into the VTA is inhibited, social interaction is impaired.

Dr. Malenka and team noted that oxytocin released in the VTA stimulates a group of neurons called "dopamine neurons," which function via dopamine signaling. Moreover, while inhibiting the release of oxytocin in that region of the brain did impact sociability negatively, it did not stop the animals' taste for pleasure-inducing drugs such as cocaine.

This is possibly the first study to confirm the existence of this mechanism, showing that oxytocin directly affects dopamine neurons in the VTA.

Crucial 'to understand how oxytocin works'

Dr. Malenka told MNT that the study "use[d] a sophisticated collection of methods to provide a brain mechanism that explains why social interactions are often pleasant and rewarding."

But he also pointed out that the main limitation it faced was the reliance on the mouse model, which may lead to some inaccuracies.

"The limitations," he explained, "are that the work was done in mice and therefore, of course, we do not know whether the same mechanisms happen in the human brain (although we think it is likely). We also use very simple behavioral assays in the mice and have to make the assumption that the social interactions we studied were 'rewarding'."

In the future, added Dr. Malenka, "We need to figure out experiments to do in people that will allow us to test whether the same mechanisms occur in the human brain and contribute to the good feeling we have when we have pleasant social interactions with our friends."

Research on the mechanisms behind the reward circuit, and the role that oxytocin plays in them, is important - especially given this hormone's potential to substantially affect social behavior.

"[O]xytocin is being tested as a potential therapeutic agent in the treatment of individuals with autism and other brain disorders which exhibit social behavior deficits. It is therefore important to understand how oxytocin works in the brain to mediate its potential therapeutic effects."

Dr. Robert Malenka

Going forward, he hopes that his team may be able to delve even deeper into the mysteries of the social reward response in the brain.

"We need to learn more about the detailed molecular mechanisms by which oxytocin modulates reward circuitry and dopamine neuron activity," he concluded.

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Comments(3)

The brain in my view after so many different conditions that go on with natural defects to trauma. Example and no one can answer this and if any one can it would help. Educated with high IQ very active and sporty until one day he fell ill and the brain was tested with so many tests that got the neurology puzzled and referred to a professor who was interested in the case. the patient over a few years had gone from healthy to a world turned in to a tomb. He went severely blind deaf, mute spinal, paralysed. and now he has nothing to communicate as he lays down 24hrs daily, dark, no sound, no feel of communication. I am his carer. After reading the amount of issues in the Medical News Today the brain is a very powerful structured item. We have much more yet to solve in our life time as yet with all the tests and variety of ailments people go through the brain as the last say. The spinal connected to brain nerve core is so incredibly complicated with the structure. And as you see look what can happen to a day to day normal person and change his life for ever.

How powerful of the most complicated maze of a human brain can create a human life to change. Heathy, sporty, very high IQ and yet the brain wipes a human to tomb of a life. He his severely blind deaf mute paralysed. Professors are baffled in this brain decease that can not be stopped as his sensory went in stages over night in each one. Turning into desperation as a carer a article Medical News Today the openness of powerful brain is not to be taken lightly. Our lives we just take for granted the next moment no vision, sound, sound, paralysed no communications or feelings. Each area as been picked up as damage from scans of the brain. Medical have far more to solve in our life time as yet with all the tests and variety of ailments people go through the brain as the last say. The spinal connected to brain nerve core is so incredibly complicated with the structure. And as you see look what can happen to a day to day normal person and change his life for ever.

It's apparent by how you construct sentences and ideas that you are having some issues. But, parsing through what I believe you are trying to communicate, seems you have had a lot of dealings with allopathic medicine and AMA certified doctors and modern pharmaceutical drugs.

That is the source of all your problems. Allopathic medicine is only good for general surgery and issues dealing with same. If you have a ruptured appendix, go to a doctor. If anything else, DO NOT SEEK THEIR ADVICE. They are college-educated idiots unable to perform basic critical thinking. While highly 'educated' what they are taught are lies and deleterious practices to human health.

Detox the body. Remember from childhood, 'you are what you eat!? Well, that is definitely true. Seek organic whole foods and avoid processed and GMO laden foods. Do not eat things stuffed in plastics, as they contain nasty chemicals that leach off into the food.

Pray and meditate. Having a deep spiritual connection to God will sort out nearly every single mental health issue. When you pray and meditate, focus on your breathing and learn how to do that effortlessly.

Do not use homeopathy, as that is B.S. Instead, seek out natural remedies and 'return to basics'. Avoid places dense with electro-smog, such as near cell phone towers and never use a cell phone against your skin. Keep it away, use the speaker portion. At home, use ethernet cables instead of WiFi.

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